DE1180483B - Process for the production of fibers with improved colorability from polymers or copolymers of acrylic acid nitrile - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: D 01 f;

D06p

German class: 29 b -3/65

Number: File number: Filing date:
Display day:

D 37608IVc / 29 b
August 6, 1957
October 29, 1964

For the sake of simplicity, the following are fibers from polymers or copolymers of acrylonitrile, which are at least about 85 percent by weight Acrylonitrile units contained in the polymer molecule, referred to as "polyacrylonitrile fibers".

There are various processes for the production and treatment of acrylic fibers, threads, yarns, Twisting, ropes, cords and the like are known to improve certain physical properties. in the general, however, are the usual processes, including the known heat treatment processes, not particularly advantageous from the viewpoint of improving the coloring property. None of the known method is capable of z. B. the ability of the fibers to improve significantly, thoroughly different from usual Dyes get permeated to the fibers practically evenly and quickly inside and to stain the surface.

Certain vinyl lactam polymers, in particular polyvinylpyrrolidone, are particularly advantageous agents to improve the dyeability of acrylic fibers when incorporated into them. Often, however, can the use of such polymeric substances as dyeing auxiliaries for acrylic fibers is only superficial Improve the dye absorption capacity of the fibers. This does not necessarily affect the dyeability the fibers are significantly improved. A complete coloration z. B. can sometimes only with great difficulties can be achieved with acrylic fibers impregnated with vinyl lactam if certain Acetate dyes can be used.

Fibers that are not thoroughly penetrated and dyed, but only the dye on the Surface and absorb in their outer parts are generally referred to as ring-colored. Polyacrylonitrile fibers, which have the tendency to fray during normal use, so that their inner Parts exposed are of little value if only ring colored. You have the very noticeable one Disadvantage of turning white or fading when the ring-colored fibers are broken up.

The invention therefore relates to a process for the production and conditioning of polyacrylonitrile fibers, to substantially increase the dyeability of the finished product, d. H. to penetrate of dyes in the fibers to improve and facilitate the ring coloring to avoid.

According to the invention, this is achieved in that fibers are obtained by conventional wet spinning processes, these are washed, drawn, if appropriate for processes for the production of fibers with improved dyeability from polymers or
Copolymers of acrylonitrile

Applicant:

The Dow Chemical Company, Midland, Mich.

(V. St. A.)

Representative:

Dr.-Ing. H. Ruschke, patent attorney,

Berlin 33, Auguste-Viktoria-Str. 65

Named as inventor:

Stanley Allen Murdock,

Thomas Cecil Spence, Concord, CaHf. (V. St. A.)

Claimed priority:

V. St. v. America August 27, 1956

(606484, 606 500)

Processed staple fibers and while they are still in the form of hydrogel, passes them through a water bath containing a vinyl lactam polymer in solution, and then steams them for about 0.5 seconds to 30 minutes under an absolute pressure of at least about 1.4 kg / cm ² treated and then dried.

It is particularly advantageous if the heat treatment is carried out by treating the fiber containing the vinyl lactam with water vapor under an absolute pressure of between about 1.76 and 4.22 kg / cm ^{a for} 1 second to 5 minutes. The fiber can be treated both in a relaxed, fully shrinkable state, such as under tension, and in an incompletely shrinkable state. After the steam treatment has ended, the fiber can be dried either in the relaxed state or under tension. It can then be dyed thoroughly with a large number of different dyes by an ordinary method, the dye penetrating well into the interior.

The colored fibers that can be obtained are not ring colored to any appreciable extent; they are more than superficially improved by the vinyl lactam polymer used as a dyeing aid.

409 709/321

Furthermore, the impregnated fibers treated according to this invention are characterized by an increased "color yield" or by an overall improvement in the general ink receptivity compared to untreated fibers containing vinyl lactam polymer are excellent.

Better and greater dyeability of the treated fibers can be obtained if they are finally dried at moderately elevated drying temperatures. The temperature used for drying of the fibers may be between room temperature and 160 ° C, are most preferably between about 110 and 150 ⁰ C.

As indicated, it is particularly advantageous to practice the invention using the acrylic fiber as Coloring aid polyvinylpyrrolidone is incorporated.

The fiber made and dried in accordance with the present invention which has an improved overall ink receptivity can easily be colored with excellent penetration with most dyes will. Conventional procedures can be used to ensure through-staining and around deep and even shades not only with acetate dyes, but also with acidic and direct pulling dyes and with vat dyes. They also have the treated fibers excellent physical properties.

example 1

A dope was prepared by dissolving about 1 part by weight of polyacrylonitrile having an average molecular weight of about 25,000 to 30,000 in about 9 parts of a 60% solution of zinc chloride in water. The spinning solution, which had a viscosity of 2000 poise at 25 ^° C., was pressed through a 0.25 mm spinneret with 300 holes into a precipitation bath which consisted of a solution of about 43.5% zinc chloride in water. The temperature of the precipitation bath was about 15 ° C. The pressed, precipitated spinning solution gave a thread-like structure of a hydrogel which was washed in distilled water at room temperature until the salt content of the hydrogel did not exceed about 0.05% based on the dry weight of the polyacrylonitrile. The washed hydrogel was simultaneously oriented by stretching and impregnated with polyvinylpyrrolidone by first stretching it in air after pulling it out of the precipitation bath and then additionally stretching it while immersing it in two successive hot aqueous baths containing dissolved polyvinylpyrrolidone. The first bath contained about 4% ^and the second bath about 0.5% polyvinylpyrrolidone. The fiber was stretched a total of 12 times; stretching was carried out twice in air and then three times and twice in the successive polyvinylpyrrolidone-containing aqueous baths. The washed and stretched hydrogel fiber contained about 8.5% - based on the dry weight of the polyacrylonitrile in the fiber - of polyvinylpyrrolidone.

A first portion (sample A) of the wet-stretched polyvinylpyrrolidone-containing hydrogel was dried in air at 150 ° C. Two other parts (Samples B and C) were placed in a pressure vessel before drying and ^{exposed to saturated water vapor at a pressure of 1.76 kg / cm 2} for about 2 minutes. Sample B was then dried under train at 15O ⁰ C for 5 minutes and dried sample C at the same temperature and for the same time in a relaxed state.

The samples were heated at 4% boiling point for about 1 hour (based on the Weight of the fiber based) of a direct dye dyed. Sample A was only in hers outer parts colored to a depth of about 10% of the diameter. Samples B and C, however had taken up the dye to a greater extent than Sample A. Besides, neither showed the Sample B nor sample C with the photomicrographic examination signs of a ring discoloration, rather, they had thoroughly incorporated the dye within their cross-sections.

It was also observed that some of the physical properties of those treated with steam were observed Samples (B and C) at least comparable to those of the untreated samples, if not noticeable had been improved. This is shown by comparisons in the table below:

sample
AIB j C 3.6
3.0
42 3.8
3.2
32 denier 3.5
3.0
33 Tear strength, g / den
Extensibility,%

The foregoing excellent results were also obtained when the procedure was repeated and the treated fiber samples have been dyed with other dyes of the large dye groups, which include acetate and vat dyes, acidic and basic dyes.

Example 2

A few more acrylic fiber samples impregnated with polyvinylpyrrolidone were, as described in Example 1, manufactured and conditioned in the same way as described in the first example, only that the treatment conditions over a range of water vapor pressures and treatment times were changed. Each of the fiber samples was then given 4% of the dye used in Example 1 colored and examined microscopically to observe color penetration. The used Treatment conditions and the results obtained are summarized in the following table also mentioning the physical properties of the treated fiber samples. For For purposes of comparison, the results are also shown in the table, those with an untreated polyvinylpyrrolidone containing comparative sample have been obtained.

fiber water Steam- Color through Tear Stretch denier steam time in urgency firm bar sample pressure Minu speed speed 3.5 kg / cm * th ring colored g / den D. Nor 1 3.5 38 times 4.2 pressure Completely E. 4.3 1.76 1 Completely 2.8 42 F. 4.1 1.76 3 Completely 2.7 44 G 4.0 1.76 6th Completely 2.8 40 H 3.5 1.4 1 ring colored 2.9 45 Ver - - 3.5 38 same

Example 3

A wet-spun, stretched fiber rope in hydrogel form, which was similar to that produced in Example 1, except that it had a polyvinylpyrrolidone content of about 8%, was further treated and thermally conditioned in accordance with the present invention by a continuous process in the course of three successive experiments was passed immediately after the final stretching stage in the heat before drying in the relaxed state at 150 ° C through a steam pipe. The stretched fiber rope in the hydrogel state was passed through the steam tube with sufficient tension to give it an additional approximately one-fold stretch during treatment. The residence time of the rope running through the steam pipe was about 1.44 seconds. The water vapor pressure in the treatment was changed during the successive tests. The treatment conditions and the results of the various tests with the fibers, which were finally dried in a relaxed state at 15O ⁰ C are listed in the following table:

denier

Water vapor pressure in the tube,

kg / cm ²

Color penetration

Tear strength, g / den

Extensibility,%

sample

2.7

1.76
Completely
3.3
40

2.3

2.81
fully 3.2
31

was. The treatment time of the fiber (sample L) in the steam pipe was about 5 minutes ^{at a steam pressure of about 1.9 kg / cm 2.} A comparison sample (sample M) of the same hydrogel, which had not been treated with water vapor, was examined together with sample L for comparison. The results were as follows:

sample L. M.
(Ver
same) denier 2.4
fully
constant
3.6
30th O Ö
Z, ö
ring
colored
3.6
37 Color penetration
Tear strength, g / den
Extensibility,%

30th

35

Example 4

The procedure of Example 3 was repeated, only the rope was thermally conditioned by this was passed through the steam pipe at a uniform linear velocity, so that this was neither stretched nor allowed to shrink during the conditioning treatment.

The polyacrylonitrile fiber hydrogel used was + .i a wet-spun, washed, and drawn fiber that has been impregnated so that it is about Contained 6.6% polyvinylpyrrolidone, but otherwise the same as the hydrogel used in the first example Similar results can be obtained when polyacrylonitrile fibers with other vinyl lactam polymers, to which polyvinylcaprolactam and other copolymers of vinylpyrrolidone and vinylcaprolactam and then treated with steam in accordance with this invention.

Claims (3)

Patent claims: 1. A process for the production of fibers with improved dyeability from polymers or copolymers of acrylonitrile which contain at least about 85 percent by weight of acrylonitrile units in the polymer molecule, characterized in that fibers are obtained by conventional wet spinning processes, they are washed, drawn, optionally processed into staple fibers and they while they are still in the form of a hydrogel, passed through a water bath containing a dissolved vinyl lactam polymer, and then treated for about 0.5 seconds to 30 minutes with steam under an absolute pressure of at least about 1.4 kg / cm ² and then dried . 2. The method according to claim 1, characterized in that the water bath as a vinyl lactam polymer Contains polyvinylpyrrolidone. 3. The method according to claim 1 or 2, characterized in that the fibers ^{are subjected to the steam treatment under an absolute pressure between about 1.75 and 4.2 kg / cm 2} for about 1 second to 5 minutes. 409 709/321 10.64 © Bundesdruckerei Berlin